Cellular upregulation of VEGF receptor expression using nanofibrillar articles

Abstract

The invention provides methods and systems for selectively upregulating the expression of a VEGF receptor in a cell using a synthetic nanofibrillar article. Exemplary embodiments relate to the upregulation of the VEGF receptor Flk-1 in endothelial cells. Cells having the selectively-upregulated VEGF receptor can be used in processes such as cell culturing, tissue engineering, cellular therapy, and drug discovery.

1 . A method for selectively up-regulating the expression of a VEGF receptor in a cell comprising a step of:
 contacting a cell comprising a VEGF receptor gene with a synthetic nanofibrillar article for a period of time wherein expression of the VEGF receptor gene becomes selectively upregulated in the cell.   
   
   
       2 . The method of  claim 1  where the VEGF receptor gene is Flk-1. 
   
   
       3 . The method of  claim 1  where the cell is an endothelial cell. 
   
   
       4 . The method of  claim 1  wherein the synthetic nanofibrillar article comprises nanofibers comprising a polyamide condensation polymer. 
   
   
       5 . The method of  claim 1  wherein the synthetic nanofibrillar article comprises nanofibers comprising a polymeric coating on a surface of the nanofibers. 
   
   
       6 . The method of  claim 5  wherein the polymeric coating on the surface of the nanofibers comprises a non-biodegradable polymer comprising a plurality of pendent amine groups. 
   
   
       7 . The method of  claim 5  wherein the polymeric coating on a surface of the nanofibers comprises a polymer covalently bonded to the surface via reacted photo-groups. 
   
   
       8 . The method of  claim 1  wherein the step of contacting is performed in vitro. 
   
   
       9 . The method of  claim 1  wherein the step of contacting is performed for a period of time of 4 hours or greater. 
   
   
       10 . The method of  claim 9  wherein the step of contacting is performed for a period of time in the range of 4 hours to 30 days. 
   
   
       11 . The method of  claim 3  wherein the endothelial cell comprises non-VEGF receptor genes VE-cadherin, Tie-2, von Willebrand Factor receptor (vWR); and PECAM, and after the period of time of contacting the endothelial cell with the synthetic nanofibrillar article an increase in expression of the Flk-1 gene is greater than any increase in expression of the VE-cadherin, Tie-2, von Willebrand Factor receptor (vWR), or PECAM genes. 
   
   
       12 . The method of  claim 11  wherein the increase in expression of the Flk-1 gene is 0.5 fold or greater than any increase in expression of the VE-cadherin, Tie-2, von Willebrand Factor receptor (vWR), or PECAM genes. 
   
   
       13 . The method of  claim 3  wherein after the period of time of contacting endothelial cells with the synthetic nanofibrillar article, the endothelial cells have a phenotype which comprises reduced stress fibers with fiber alignment between multiple endothelial cells. 
   
   
       14 . The method of  claim 3  wherein after the period of time of contacting endothelial cells with the synthetic nanofibrillar article, the endothelial cells have a phenotype that comprises a multilayered arrangement without actin defined boarders. 
   
   
       15 . A method for treating a medical condition in a subject comprising steps of:
 providing cells comprising a VEGF receptor gene,   contacting the cells with an synthetic nanofibrillar article for a period of time wherein expression of the VEGF receptor gene becomes selectively upregulated in the cells, and   implanting the cells in which the VEGF receptor gene has become selectively upregulated in a subject to treat a medical condition.   
   
   
       16 . The method of  claim 15  wherein the cells are endothelial cells and the VEGF receptor gene is Flk-1. 
   
   
       17 . The method of  claim 15  wherein the cells in which the VEGF receptor gene has become selectively upregulated are implanted in a subject having experienced an ischemic event, tachycardia, atherosclerosis, hypotension, and/or thromboembolism. 
   
   
       18 . The method of  claim 15  wherein the cells in which the VEGF receptor gene has become selectively upregulated are implanted at an ischemic tissue site selected from the group consisting of cardiac tissue, cerebral tissue, kidney tissue, lung tissue, and spleen tissue. 
   
   
       19 . The method of  claim 15  wherein the cells in which the VEGF receptor gene has become selectively upregulated are implanted in a subject to promote an angiogenic or vasculogenic response. 
   
   
       20 . A method for identifying a compound that affects or interacts with cells wherein a VEGF receptor has been selectively upregulated, comprising steps of:
 providing cells comprising a VEGF receptor,   contacting the cells with a synthetic nanofibrillar article for a period of time wherein expression of the VEGF receptor gene becomes selectively upregulated in the cells,   applying a compound to the cells in which expression of the VEGF receptor gene is selectively upregulated, and   determining if the compound affects or interacts with cells in which expression of the VEGF receptor gene is selectively upregulated as compared to a control.   
   
   
       21 . The method of  claim 20  wherein the cells are endothelial cells and the VEGF receptor gene is Flk-1. 
   
   
       22 . The method of  claim 20  wherein the step of determining comprises determining if the compound binds to Flk-1.